Photographic products and processes using alkali permeable co-polymeric layers



1952 H. c. HAAS 3,061,428

PHOTOGRAPHIC PRODUCTS AND PROCESSES usmc ALKALI PERMEABLE (JO-POLYMERIC LAYERS Filed Dec. 17, 1958 I4 L/R-SILVER HALIDE EMULSION LAYER VINYL PHTHALlMIDE-ACRYLIC ACID GOPOLYMER LAYER CONTAINING A COLOR- PROVIDING SUBSTANCE \SUPPORT F I G.

BLUE-SENSITIVE EMULSION VINYL PHTHALlMlDE-ACRYLIC ACID COPOLYMER LAYER CONTAINING A 36 HH/H/HHHHH/ YELLOW DYE DEVELOPER 34 INTERLAYER 32 /GREEN-SENSITIVE SILVER HALIDE MULSION LAYER VINYL PHTHALlMlDE-ACRYLIO ACID 2e COPOLYMER LAYER CONTAINING A 26 MAGENTA DYE DEVELOPER 24 'NTERLAYER 22 RaglgEgfilTrpliYERslLvER HALIDE 2O VINYL PHTHALlMIDE-ACRYLIC ACID COPOLYMER LAYER CONTAINING A CYAN DYE DEVELOPER SUPPORT FIG.2

IN V EN TOR.

AT RNEYS E it 3,061,428 Patented Oct. 30, 1962 fie 3,061,428 PHOTGGRAPHIC PRODUCTS AND PRQCESSES USING ALKALI PERMEABLE (ID-POLY- MERIC LAYERS Howard C. Haas, Arlington, Mass., assignor to Polaroid Corporation, Cambridge, Mass, a corporation of Delaware Filed Dec. 17, 1958, Ser. No. 781,009 16 Claims. or. ss-zs The present invention is concerned with photography and more particularly with novel photographic products and novel photographic processes utilizing said products.

One object of this invention is to provide novel photosensitive elements for color diffusion transfer processes comprising at least one silver halide emulsion layer and at least one layer of a polymeric material having a colorproviding substance disposed therein, said polymeric material being a copolymer of vinyl phthalimide and an 8- unsaturated carboxylic acid.

Another object of this invention is to provide improved color diffusion transfer processes utilizing said photosensitive elements.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the product possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing wherein:

FIGURE 1 is a diagrammatic cross-sectional view of one embodiment of a photosensitive element of this invention; and

FIG. 2 is a diagrammatic cross-sectional view of one embodiment of a multilayer photosensitive element within the scope of this invention.

The present invention is particularly related to color diffusion transfer processes. In such processes a photosensitive element including a silver halide emulsion layer is exposed to create therein a latent image. The latent image is developed and, concurrent with and under the control of this development, an imagewise distribution of mobile color-providing substances is formed. At least a portion of these color-providing substances is transferred by means of an alkaline aqueous processing liquid to a superposed image-receiving layer to form a colored image thereon. As examples of such processes, mention may be made of the processes disclosed and claimed in the copending U.S. applicationof Howard G. Rogers, Serial No. 748,421, filed July 14, 1958, now U.S. Patent No. 2,983,606 issued May 9, 1961, as a continuation-in-part of U.S. application Serial No. 415,073, filed March 9, 1954 (now abandoned), wherein dye developers (i.e., compounds which contain in the same molecule both the chromophoric system of a dye and also a silver halide developing function) are the color-providing substances, the processes claimed and disclosed in U.S. Patent No. 2,647,049, issued July 28, 1953 to Edwin H. Land, Wherein color developers are employed to develop the latent image and color couplers are the color-providing substances, and the processes disclosed in U.S. Patent No. 2,774,668, issued December 18, 1956, to Howard G. Rogers, wherein complete, preformed dyes are used as the color-providing substances. It should be understood that the term colorproviding substances as used herein refers to organic materials such as dyes, including dye developers and dye intermediates.

In an especially useful mode of carrying out color diffusion transfer processes such as described above, the color-providing substances are disposed in a separate alkall-permeable layer in the photosensitive element. The separate alkali-permeable layer may be placed either in front of or behind the photosensitive emulsion with which it is associated; however, in a preferred embodiment it is placed behind, i.e., on the side of the emulsion which is most distant from the photographed subject when the emulsion is exposed, and preferably also adapted to be most distant from the image-receiving element when in superposed relationship therewith. In carrying out the processes, the photosensitive element is exposed and wetted with an aqueous alkaline processing solution, for example by immersing, coating, spraying, flowing, etc., in the dark, and the photosensitive element is superposed prior to, during or after wetting on an image-receiving element. In a preferred embodiment the aqueous alkaline processing solution contains a viscosity-increasing compound and is applied to the photosensitive element in a substantially uniform layer as the photosensitive element is brought into superposed position with the imagereceiving element. The alkaline aqueous processing solution permeates the photosensitive emulsion and alkalipermeable layers and solubilizes the color-providing substances to provide a substantially uniform distribution of the color-providing substances therein. As the processes proceed, the exposed silver halide image is developed and an imagewise distribution of mobile color-providing substances is formed. At least a portion of the color-providing substances is transferred to and imbibed on the imagereceiving element to form the image thereon. The image is viewed by stripping the image-receiving element from the photosensitive element.

When the color-providing substances are incorporated into a separate alkali-permeable layer, it is desirable that said alkali-permeable layer have good dry adhesion to the other layers present in order to withstand the stresses and strains such a layer would be normally subjected to during, for example, coating operations, and egpecially to Withstand the stresses and strains which are encountered if the photosensitive element is a part of a roll film unit. Such adhesion must be achieved in the presence of relatively high amounts of the color-providing substances which generally have little or no adhesiveness in themselves and which often have an adverse effect on the bonding. It is further desirable, and no less important, that said alkalipermeable layer have good wet adhesion to the other layers present; otherwise, during processing, upon stripping the image-receiving element from the photosensitive element, delamination may take place and portions of the photosensitive element' would adhere to the surface of the imagereceiving element and mar the quality of the tranfer image. It is still further desirable that the alkali-permeablelayer readily release the color-providing substances in order to make the maximum amount of said substances available for forming the image. In the past, film-forming polymers such, for example, as cellulose acetate hydrogen phthalate have been proposed as materials for the alkali-permeable layers.

It has been discovered that when the color-providing substances are disposed in a layer comprising a copolymer of vinyl phthalimide and an a d-unsaturated carboxylic acid, said copolymers provide wet and dry adhesion which is superior to that obtained with cellulose acetate'hydrogen phthalate and, further, said copolymers readily release the color-providing substances.

The usefulness of the copolymers of this invention is especially demonstrable when dye developers-are the color-providing substances. Dye developers, as noted above, are compounds which contain in the same molecule both the chromophoric system of a dye and also a silver halide developing function. By a silver halide developing function is meant a radical which is capable of developing an exposed silver halide image. Particularly useful dye developers are those in which the silver halide developing function is provided by a benzenoid developing group. A preferred benzenoid developing radical in such compounds is a hydroquinonyl radical. Examples of representative dye developers are given in the previously mentioned US. application of Howard G. Rogers, Serial No. 748,421. Additional useful dye developers are described in the following copending US. applications:

Application Serial No. 449,514, filed August 12, 1954, in the names of Elkan R. Blout and Myron S. Simon, now abandoned and replaced by continuation-in-part application Serial No. 849,727, filed October 30, 1959.

Application Serial No. 471,542, filed November 26, 1954, in the names of Elkan R. Blout, Saul G. Cohen, Milton Green, Howard G. Rogers, Myron S. Simon and Robert B. Woodward, now abandoned and replaced by continuation-in-part application Serial No. 1,442, filed January 11, 1960.

Application Serial No. 478,922, filed December 30, 1954, in the names of Elkan R. Blout, Marilyn R. Cohler, Milton Green, Myron S. Simon and Robert B. Woodward, now abandoned and replaced by continuation-in-part application Serial No. 824,785, filed July 3, 1959.

Application Serial No. 612,045, filed September 25, 1956, in the names of Elkan R. Blout, Milton Green and Howard G. Rogers, now abandoned and replaced by continuation-in-part application Serial No. 144,816, filed October 18, 1961.

Application Serial No. 612,052, filed September 25, 1956, in the names of Milton Green and Howard G. Rogers, now abandoned and replaced by continuation-inpart application Serial No. 165,930, filed January 12, 1962.

Application Serial No. 612,053, filed September 25, 1956, in the name of Myron S. Simon.

Application Serial No. 612,054, filed September 25, 1956, in the names of Helen P. Husek and Myron S. Simon.

Application Serial No. 612,055, filed September 25, 1956, in the name of Helen P. Husek.

Application Serial No. 755,804, filed August 18, 1958, in the names of Elkan R. Blout, Saul G. Cohen, Milton Green and Myron S. Simon.

In color diifusion transfer processes employing dye developers, the dye developer, as mentioned previously for color-providing substances in general, is preferably placed in a separate alkali-permeable layer behind the photosensitive layer. Upon processing, the alkaline aqueous processing solution permeates to the separate alkali-permeable layer and solubilizes the dye developer therefrom. As the process proceeds, the latent silver halide image in the photosensitive element is developed and, as a result of this development, the dye developer in the exposed areas is oxidized and substantially immobilized. At least a portion of the unreacted dye developer is imbibed on a superposed irnage-receiving element to create thereon the positive dye image. In such processes the immobilization of the dye developers in the exposed areas is apparently due, at least in part, to a change in the solubility characteristics of the dye developer upon oxidation. It may also be due in part to a tanning effect on the emulsion by the oxidized developer and to localized exhaustion of alkali due to development.

FIG. 1 of the accompanying drawing illustrates one embodiment of a photosensitive element for use in color diffusion transfer processes wherein a vinyl phthalimideacrylic acid copolymer is used as the material for a separate alkali-permeable layer. The photosensitive element shown therein comprises a support 10, a layer 12 of vinyl it phthalimide-acrylic acid copolymer containing a colorproviding substance and a photosensitive layer 14.

In preparing photosensitive elements of the type mentioned above and in preparing other photosensitive elements within the scope of this invention, the copolymer layers may be conveniently applied from coating solutions containing the desired copolymer. The preferred coating solutions comprise 2 to 10% of copolymer; however, this amount may be varied to suit particular needs. The coating and drying operations may be carried out according to procedures well known to the art. The color-providing substances which are to be disposed in the separate alkali-permeable layer may be incorporated into the coating solution and applied therewith, or they may be imbibed onto the layer after its application. When the color-providing substances are incorporated into the coating solutions, they may be dispersed or solubilized therein, depending upon the color-providing substance itself, the solvent used and the state desired for the diffusion transfer processes. As examples of suitable solvents which can be used in preparing the coating solutions, mention may be made of methanol, ethanol, and methanol-tetrahydrofuran mixtures. When the coating solution is applied directly to a support such, for example, as baryta, cellulose acetate, etc., said support may be first subcoated with a suitable subbing material to further enhance the adhesion.

The copolymers of this invention are also suitable as materials for alkali-permeable layers in integral multilayer photosensitive elements for use in multicolor diffusion transfer processes. As an example of such photosensitive elements, mention may be made of the photosensitive elements disclosed and claimed in the copending US. application of Edwin H. Land and Howard G. Rogers, Serial No. 565,135, filed February 13, 1956, wherein at least two selectively sensitized photosensitive strata are superposed on a single support and are processed, simultaneously and without separation, with a single common image-receiving element. A suitable arrangement of this type comprises a support carrying a red-sensitive silver halide emulsion stratum, a green-sensitive silver halide emulsion stratum and a blue-sensitive silver halide emulsion stratum, said emulsions having associated therewith, respectively, a cyan dye developer, a magenta dye developer and a yellow dye developer. In one of the preferred embodiments of photosensitive elements of this type, the dye developers are disposed in separate alkali-permeable layers behind the photosensitive silver halide emulsion stratum with which they are associated. As in monochromatic photosensitive elements, the copolymers of this invention, when used as materials for the alkali-permeable layers, provide superior wet and dry adhesion, as compared with cellulose acetate hydrogen phthalate, and also readily release the colorproviding substances. When the copolymers of this invention are used in such multicolor film units, at least one and usually all the color-providing substances are disposed in layers comprising the copolymers of this invention. However, it should be understood that in certain instances it may be desirable for reasons such, for example, as permeation rates, transfer rates, etc., to dispose some of the color-providing substances directly into the silver halide emulsion layers or in alkali-permeable layers of materials other than those disclosed herein.

A multilayer photosensitive element of the type mentioned above is illustrated in FIG. 2 of the accompanying drawing. A support 20 carries a layer 22 of a vinyl phthalimide-acrylic acid copolymer containing a cyan dye developer; a layer 24 of a red-sensitive silver halide emulsion; an interlayer 26, e.g., polyvinyl alcohol, gelatin, etc.; a layer 28 of a vinyl phthalimide-acrylic acid copolymer containing a magenta dye developer; a layer 30 of a green-sensitive silver halide emulsion; an interlayer 32; a layer 34 of a vinyl phthalimide-acrylic acid copolymer containing a yellow dye developer; and an V outermost layer 36 of a blue-sensitive silver halide emulsion. In certain instance, for example when the yellow dye developer is not present in a state capable of functioning as a filter, a yellow dye filter is placed in interlayer 32.

Although the vinyl phthalimide-acrylic acid copolymer layers in the photosensitive element of FIG. 2 are shown principally adhered to gelatin or polyvinyl alcohol layers, it should be noted that the copolymers of this invention show good adhesion to hydrophilic, alkali-permeable filmforming materials in general. As a result of this, wide discretion may be exercised in selecting film-forming materials as carriers for the silver halide emulsion, interlayers and other layers which may be adjacent to the copolymer layers. For example, one may replace gelatin, which is the carrier usually used in the silver halide emulsion layers, in Whole or in part, with gelatin substitutes such, for example, as cellulose ethers, polyvinyl alcohols, partially hydrolyzed organic esters of polyvinyl alcohols, acetals of poly-vinyl alcohols, etc. Similar discretion may be exercised in selecting the film-forming materials for the interlayers and other layers. In certain instances, if desired, the copolymers of this invention may be used as the interlayers and in other layers which may be present.

Although the copolymers of this invention provide good adhesion in and by themselves, in certain instances their adhesion to adjacent layers may be enhanced by incorporating a small amount of said copolymers into the layers to which they are to be adhered. The amount of copolymer, so incorporated, may be varied to suit particular needs; generally, however, an amountcomprising about by weight, of the adjacent carrier material will provide the increased adhesion.

Both the monochromatic and multicolor photosensitive elements within the scope of this invention may be used in roll films which contain a plurality of photosensitive frames. The photosensitive elements of this invention are especially useful in composite roll film units intended for use in a Polaroid Land Camera, sold by Polaroid Corporation, Cambridge 39, Massachusetts, or a similar camera structure such, for example, as the camera forming the subject matter of U.S. Patent No. 2,435,717, issued to Edwin H. Land on February 10, 1948. In general, such composite roll film units comprise a photosensitive roll, a roll of image-receiving material and a plurality of pods containing an aqueous alkaline processing solution. The rolls and pods are so associated with each other that, upon processing, the photosensitive element may be superposed on the image-receiving element and the pods may be ruptured to spread the aqueous alkaline processing solution between the superposed elements. The nature and construction of the pods used in such units are well known to the art. See, for example, US. Patent Nos. 2,453,181 and 2,634,886, issued to Edwin H. Land.

The copolymers for use in preparing the photosensitive elements of this invention may be prepared by copolymerizing vinyl phthalimide with an tap-unsaturated carboxylic acid. The polymerization may be catalyzed and carried out under conditions well known to the art. The preferred u,/8-unsaturated carboxylic acids for use in preparing the copolymers of this invention are those which contain less than six carbon atoms. As examples of such acids, mention may be made of acrylic acid, methacrylic acid and crotonic acid. In polymerizing the copolymers of this invention, the molar ratio of the vinyl phthalimide monomer to the v n-unsaturated carboxylic acid monomer may be varied to suit particular needs; however, it has been found that especially useful copolymers are produced when said ratio is at least 1 to 1 and more particularly about 7 to 3.

It will be understood that unless the reaction rates of the monomers are about equal, the compositions of the polymers produced at diflerent stages of the polymerization will vary. The preferred polymers for use in this invention are the initial polymers produced.

The following nonlimiting example illustrates the preparation of a copolymer within the scope of this invention.

Example 1 22 gms. of N-vinyl phthalimide and 4.32 gms. of acrylic acid (7 to 3 molar ratio) were dissolved in 25 ml. of benzene containing 0.0789 gm. of azobisisobutyronitrile and heated at 65 C., under nitrogen, for eight hours. The initial polymer produced was precipitated into hexane, washed with hexane and dried. The dried product was insoluble in water and soluble in dioxane, dioxane-methanol and 2% sodium hydroxide.

The following nonlimiting example illustrates the prep aration and use of a photosensitive element within the scope of this invention.

Example 2 then processed by spreading an aqueous processing solution comprising:

Percent Sodium carboxymethyl cellulose 5.0 Sodium hydroxide 2.0 2,5-bis-ethyleneiminohydroquinone 0.4 1-phenyl-3-pyrazolone 0.6 6-nitrobenzimidazole 0.12

between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprised a cellulose acetate-coated baryta paper which had been coated with an ethanol solution containing 4% of Nylon Type F 8 (trade name of E. I. du Pont de Nemours & Co., Wilmington, Delaware, for N-methoxymethyl polyhexamethylene adipamide). After an imbibition period of approximately one minute, the image-receiving element was separated and contained a dense yellow positive dye image of the photographed subject. No signs of wet delamination in the photosensitive element were observed.

In the above example, the dry adhesion of the copolymer layer was tested by adhering a strip of an adhesive film to the photosensitive element, stripping it from the element and observing for delamination. The photosensitive element, prepared in the above example, was superior to similar photosensitive elements prepared with cellulose acetate hydrogen phthalate as the dye carrier. The dry adhesion was further tested by bending the photosensitive elements over rods of various diameters and examining for delamination. In each instance, the photosensitive elements of this invention could be bent to a sharper angle, than similar elements using cellulose acetate hydrogen phthalate as the carrier, without showing signs of delamination.

As mentioned previously, the polymers of this invention may be used in integral multilayer photosensitive elements such as those disclosed in the copending application, Serial No. 748,421.

As examples of suitable coating solutions which may he used to apply the cyan, magenta and yellow dye developer layers in three-color negatives in such elements, mention may be made of:

(1) A methanol-tetrahydrofuran solution (1 to 1 by volume) comprising 5.5% of 1,4-bis-[B-(2,5dihydroxyphenyl)-isopropylamino]-anthraquinone (a cyan dye developer prepared in a manner similar to that disclosed in 7 the previously mentioned copending application No. 478,922) and 2% of a vinyl phthalimide-acrylic acid copolymer, prepared as in Example 2.

(2) A methanol-tetrahydrofuran solution (1 to 1 by volume) comprising 3.5% of 2-[p-(2,5,dihydroxyphenethyl) -phenylazo]4-n-propoxy-1 naphthol (a magenta dye developer prepared in a manner similar to that disclosed in the previously mentioned copending application No. 612,045) and 2% of a vinyl phthalimide-acrylic acid copolymer, as prepared in Example 1.

(3) A methanol-tetrahydrofuran solution (1 to l by volume) comprising 3% of 1-phenyl-3-N-n-hexyl-carbamyl 4 [p-(2',5'-dihydroxyphenethyl)-phenylazo]-5- pyrazolone (a yellow dye developer prepared in a manner similar to that disclosed in the previously mentioned copending application No. 612,045) and 2% of a vinyl phthalimideacrylic acid copolymer, as prepared in Example 1.

The copolymers of this invention are further suitable for use in screen type photosensitive elements such as disclosed in the aforementioned application of Howard G. Rogers, Serial No. 748,421 and also the copending application of Edwan H. Land, Serial No. 448,441, filed August 9, 1954, now US. Patent No. 2,968,554 issued January 17, 1961, wherein at least two selectively sensitized silver halide emulsions are arranged in the form of a screen and the color-providing substances, as in multilayer photosensitive elements, are preferably placed in a separate alkali-permeable layer in back of the photosensitive emulsion with which they are associated.

Since certain changes may be made in the above product and process without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A photosensitive element comprising a support, said support having on one side a polymeric layer having a color-providing substance selected from the group consisting of dyes and dye intermediates disposed therein and a silver halide emulsion layer contiguous with said polymeric layer, said polymeric layer comprising a copolymer of vinyl phthalimide with an a,,8-unsaturated aliphatic monocarboxylic acid comprising less than six carbon atoms.

2. A photosensitive element as defined in claim 1 wherein said color-providing substance is a dye developer, said dye developer being a compound which is both a silver halide developing agent and a dye.

3. A photosensitive element as defined in claim 1 wherein said polymeric layer is between said support and said silver halide emulsion layer.

4. A photosensitive element as defined in claim 1 wherein the molar ratio of vinyl phthalimide monomer to nap-unsaturated carboxylic acid monomer used to prepare said copolymer is at least about 1 to l.

5. A photosensitive element as defined in claim 4 wherein said molar ratio is about 7 to 3.

6. A photosensitive element comprising a plurality of photosensitive silver halide emulsions, each of said emulsions being selectively sensitized to different portions of the spectrum, a dye developer associated with each of said emulsions, said dye .developer being a compound which is both a silver halide developing agent and a dye, at least one of said dye developers being disposed in a polymeric layer contiguous with the emulsion with which it is associated, said polymeric layer comprising a copolymer of a vinyl phthalimide and an :,fl-l1lil5fltllf3lfid aliphatic monocarboxylic acid comprising less than six carbon atoms.

7. A photosensitive element as defined in claim 6 wherein said polymeric layer is behind the silver halide emulsion layer with which it is associated.

8. A photosensitive element as defined in claim 6 wherein the molar ratio of vinyl phthalimide monomer to nae-unsaturated carboxylic acid monomer used to prepare said copolymer is at least about 1 to l.

9. A photosensitive element as defined in claim 8 wherein said molar ratio is about 7 to 3.

10. In a process of forming a photographic image in color wherein a latent image contained in an exposed silver halide emulsion layer of a photosensitive element is developed to provide an imagewise distribution of color-providing substances selected from the group consisting of dyes and dye intermediates in said emulsion, and said imagewise distribution of color-providing substances is transferred by an aqueous alkaline processing solution to a superposed image-receiving layer to impart to said image-receiving layer a color image, the improvement of having the color-providing substance in a polymeric layer behind the silver halide emulsion and, during processing, permeating said photosensitive element with said aqueous alkaline processing solution and solubilizing said color-providing substances from said polymeric layer, said polymeric layer comprising a copolymer of vinyl phthalimide and an n p-unsaturated aliphatic monocarboxylic acid comprising less than six carbon atoms.

11. A process as defined in claim 10 wherein the molar ratio of vinyl phthalimide monomer to n p-unsaturated carboxylic acid monomer used to prepare said copolymer is at least about 1 to l.

12. A process as defined in claim 11 wherein said molar ratio is about 7 to 3.

13. In a process of forming transfer images in color which comprises exposing a photosensitive element containing a silver halide emulsion layer and a polymeric layer, said polymeric layer containing a dye developer, said dye developer being a compound which is both a silver halide developing agent and a dye permeating said photosensitive element with an aqueous alkaline processing solution and solubilizing at least a portion of said dye developer from said polymeric layer, developing the latent image in the exposed emulsion in the presence of said dye developer whereby said dye developer is immobilized in exposed areas but is mobile in unexposed areas, thereby providing an imagewise distribution of mobile dye developer, and transferring at least a portion of said mobile dye developer to a superposed imagerecerving element to form a positive image, the improvement of having the dye developer in a polymeric layer comprising a copolymer of vinyl phthalimide and an a,fi-unsaturated aliphatic monocarboxylic acid comprising less than six carbon atoms.

14. A process as defined in claim 13 wherein said 1polymeric layer is behind said silver halide emulsion ayer.

15. A process as defined in claim 13 wherein the molar ratio of vinyl phthalimide monomer to a a-B-unsaturated carboxylic acid monomer used to prepare said copolymer is at least about 1 to 1.

16. A process as defined in claim 15 wherein said molar ratio is about 7 to 3.

References Cited in the file of this patent UNITED STATES PATENTS 2,276,840 Hanford et al Mar. 17, 1942 2,662,822 Land Dec. 15, 1953 2,686,717 Land Aug. 17, 1954 2,774,668 Rogers Dec. 18, 1956 2,831,826 Coover et al Apr. 22, 1958 2,892,710 Cohler et a1 June 30, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. $061,428 October 30, 1962 Howard Co Haas It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 2 for "instance" read instances line 54, for "2 453,181" read 2,543,181 column 7, line 5, for "2[p(2' ,5 dih xyp hewn read 2[p(2' ,5 dihydroxyphenline 23, for 'Edwan read Edwin column 8, line 58., for "a (1-13unsaturated read 0MB unsaturated Signed and sealed this 31st day of December 1963..

(SEAL) Attest: ERNEST W. SWIDER EDWIN L, REYTNOLDS Ac t i g Commissioner of Patents Attesting Officer 

10. IN A PROCESS OF FORMING A PHOTOGRAPHIC IMAGE IN COLOR WHEREIN A LATENT IMAGE CONTAINED IN AN EXPOSED SILVER HALIDE EMULSION LAYER OF A PHOTOSENSITIVE ELEMENT IS DEVELOPED TO PROVIDE AN IMAGEWISE DISTRIBUTION OF COLOR-PROVIDING SUBSTANCES SELECTED FROM THE GROUP CONSISTING OF DYES AND DYE INTERMEDIATES IN SAID EMULSION, AND SAID IMAGEWISE DISTRIBUTION OF COLOR-PROVIDING SUBSTANCES IS TRANSFERRED BY AN AQUEOUS ALKALINE PROCESSING SOLUTION TO A SUPERPOSED IMAGE-RECEIVING LAYER TO IMPART TO SAID IMAGE-RECEIVING LAYER A COLOR IMAGE, THE IMPROVEMENT OF HAVING THE COLOR-PROVIDING SUBSTANCE IN A POLYMERIC LAYER BEHIND THE SILVER HALIDE EMULSION AND, DURING PROCESSING, PERMEATING SAID PHOTOSENSITIVE ELEMENT WITH SAID AQUEOUS ALKALINE PROCESSING SOLUTION AND SOLUBILIZINGK SAID COLOR-PROVIDING SUBSTANCES FROM SAID POLYMERIC LAYER, SAID POLYMERIC LAYER COMPRISING A COPOLYMER OF VINYL PHTHALIMIDE AND AN A,B-UNSATURATED ALIPHATIC MONOCARBOXYLIC ACID COMPRISING LESS THAN SIX CARBON ATOMS. 